Is it possible to get pregnant and still have your period?

My bf and I had sex (with protection as always) and we always inspect the condom after and it was all good then I got my period a day or two later. But after my period ended I’ve been super nauseous everyday and getting headaches and (sorry TMI) slight diarrhea. I’m worried and confused

Edit:: thank you guys so much for your help and responses! I took 3 pregnancy tests and they were all negative!